Papermaking machine



4 Sheets-Sheet l ...w E n N \o l5 IV @J m.

R. M. Elss ETAL.4

PAPERMAKING MACHINE Jan. 24, 1967` Filed March ll, 1965 Jam.v 24, 1967R. M. E155 ETAL PAPERMAKNG MACHINE Filed March 11, 1965 4 Sheets-Sheet 2FIG,.2.

Y R. M. Else ETAL PAPERMAKI-NG MACHINE Filed March 11, 1965L 4Sheets-Sheet 5 Jn 24, 1957 R. M. Elss ETAL 3,299,530

PAPERMAKING MACHINE Filed March l1, 1965 4 Sheets-Sheet L FIG.5. 48

United States Patent @nice staats@ Patented Jan. 24, 1967 3,299,530PAPERMAKING MACHINE Robert M. Eiss and .loseph B. Webb, Neenah, Wis.`asi signers to Kimberly-Clark Corporation, Neenah, Wis.,

a corporation of Delaware Filed Mar. 11, 1965, Ser. No. 438,837 6Claims. (Cl. 34 124) The invention relates to steam heated drier drums,which may be used in pape-rmaking machines, for example, and moreparticularly to condensate drainage devices for such drier drums.

Papermaking machine drying sections generally include a plurality ofdrier drums, each of which comprises a cylindrical shell, spaced headsextending radially across the shell to close the open ends thereof,carrying means for journlalling the shell, means for introducing steaminto the interior of the shell, and means for Withdrawing steamcondensate therefrom. The paper web travels serially over these drums insuch a drying section. A Yankee drier `drum has substantially the samestructural .arrangement as the drier drums in the drying sections justmentioned; however, a Yankee drier drum is ordinarily of substantiallygreater diameter; and only a single one of these drums is generallyused, as in connection with tissue or lightweight webs.

On modern high speed tissue making machines, the machines and thevassociated drier drums run at speeds up to 4,000 to 5,000 feet perminute. Steam condensing on the inner wall of a rotating drier drum insuch a machine forms condensate which must be continually removed inorder to obtain good heat transfer. The condensate is held against theshell by centrifugal force which presses the fluid out in a thin sheetcovering the entire inner wall of the drum. The sheet of paper or tissuebeing dried on the outer wall of the drum is usually very sensitive toany change in heat transfer through the wall; and, assuming that acondensate removal system causes the sheet of condensate within the drumto be of unequal thickness, the heat transferring characteristics of thedrum across its surface are changed, so that the paper or tissue isthereby caused to run wet in streaks or bars according to the patterncreated by the condensate removal system.

Available condensate siphons draw off the condensate locally at a numberof places within therdrum and may include two or more manifoldsextending lengthwise of the drum adjacent its inner surface and havingoutlet tubes connecting the manifolds with a journal of the drum throughwhich the condensate may discharge. The condens-ate inlets to themanifolds are substantially open with respect to the outlet tubes,iandthere vis no substantial pressure drop between the inlets and outletstubes; and, therefore, the rate at which the condensate is `dnawn off isgreater in the areas of the outlet tubes than in areas away somedistance from these tubes. The condensate is thus not uniform inthickness on the inside of the drum, and the drying rate of the drumthus is not uniform on the complete drum surface. ln one particular typeof -manifold condensate withdrawal system, a pair of manifolds extendlengthwise of the `drier drum adjacent the inne-r drum surface, and eachof these manifolds has a plurality of holes drilled into it extendinggenerally tangentially of the inner drum surface. The steam sweepsacross the face of the sheet of water condensate into these holes andsweeps water from the inside surface of the drum into these holes andthereby into the associated manifold. Since centrifugal force iseffective on the condensate entering the manifolds, it tends to lie inthe bottom of each manifold; however, immediately in front of the outlettubes that connect the manifold with the journal of the drier drum, thesteam velocity is high enough to draw up water from the inside surfaceof the manifold at these points so that the inlet holes in the lowerface of the manifold adjacent to the outlet tubes draw condensate moreeffectively than those located some distance from each side of theoutlet tube. This unequal flow through the manifold inlet openingscauses an undesirable, unequal temlperature profile across the drierdrum.

It is an object of the present invention to provide an improvedcondensate removal system of the manifold type which is so constructedthat there is a substantially equal rate of condensate withdrawal by themanifolds from one end to the other end of the drum.

In brief, we accomplish this object by providing a plurality oflongitudinally extending manifolds within a drier drum, each having aplurality of spaced small diameter withdrawal tubes extending into itand terminating in close proximity to the inner surface of the drierdrum so that condensate may enter the tubes from the internal drumsurface. Each manifold has a smaller number of larger `diameter outlettubes connecting it with the axle and journal of the drier drum throughwhich condensate may flow, and these larger diameter tubes extend intothe manifold beyond the inner ends of the small diameter tubes. A 'pondof water tends to lcollect due to centrifugal force within each manifoldon its outermost surface, and the larger diameter tubes draw from thepond of water rather than directly from the small diameter tubes andtend to even out the draw and condensate flow through the small diametertubes. The small diameter withdrawal tubes remote from the largerdiameter outlet tubes are also preferably made shorter than the smalldiameter tubes closer to the large diameter outlet tubes for furtherevening of the ow of condensate through the small diameter tubes. Thisconstruction in which the small diameter tubes extend radially inwardlyfarther than the inlet ends of the larger diameter tubes also overcomescondensate flooding at the inner ends of the small diameter tubes whichwould tend to block condensate flow through the small diameter tubes.

The invention consists of the novel constructions, arrangements anddevices to be hereinafter described and claimed for carrying out theabove-stated objects, and such other objects, as will be apparent fromthe following description of a preferred form of the invention,illustrated with reference to the accompanying drawings, wherein:

FIG. l is a longitudinal sectional view of a Yankee drier drumincorporating the principles of the invention;

FIG, 2 is a sectional View taken on line 2 2 of FIG. 1;

FIG. 3 is a sectional view on an enlarged scale taken on line 3 3 ofFIG. 1;

FIG. 4 is an elevational view taken on line 4 4 of FIG. 3; and

FIG. 5 is a sectional view on an enlarged scale taken on line 5 5 ofFIG. 4.

Like characters of reference designate like parts in the several views.

Referring now to the drawings, the illustrated drier drum may be seen tocomprise a thin cylindrical outer shell 10 which is rigidly secured Iatits ends to a pair of relatively flat ring-shaped heads 11 and 12supported by a hollow central axle or shaft 13. The shell 10 is providedat each with an integral bolting flange 14 which is machined to matewith a similar peripheral flange 15 on the adjacent head. The rigidattachment of the shell to each head may be made, as shown, by means ofa plurality of bolts 16 inserted from the inside of the shell and drawnup by nuts on the outside of the head. Each of the heads 11 and 12 isprovided with a manhole 17 to sprovide access to the interior of thedrum for assembly and maintenance.

A short cylindrical section 18 provided at its inner end 3 with amachined bolting flange 19 is formed integrally with each of the heads11 and 12 and extends inwardly at a radial location and is intermediatethe inner and outer edges of the head. A plurality of heavy stayingmembers 20 extend between the heads longitudinally of the drier and arexed with respect to the flanges 19 by means tof flanges 21 formed on thestaying members and bolts 22 that extend through the anges 19 and 21.The purpose `of the staying members 20 is to control the bowing of theheads 11 and 12 and to eliminate stress occurring in the shell 10 at ornear its connections to the heads. t

The shell 10 and heads 11 and 12 are -of cast construction, and thecentral shaft 13 is also of cast construction and is formed in twohalves 23 and 24. The halves 23 and 24 are provided with flanges 25 and26, and bolts 27 extend through the flanges to x the halves 23 and 24together. A separator 28 is formed in the half 24 so as t-o provide twoseparate compartments 29 and 30 in the axle 13.

The shaft 13 near each end is provided with an enlarged bolting ange 31,and each head 11 and 12 is provided with a flange 32 that meets vwiththe flange 31; and the flanges 31 and 32 are xed together by means ofbolts 33. The shaft 13 is extended at each end to provide journals 34for rotatably supporting the drier in suitable bearings, a shaftextension 35 being provided at one end 4of the shaft 13 for mounting `adriving gear or sprocket or the like. The shaft 13 at its end isprovided with bores 36 and 37, respectively, in communication with thechambers 29 and 30; and the bores 37 and 36 may be utilized,respectively, for providing steam under pressure into the compartment 30and for withdrawing the steam condensate from the compartment 29.

A drier drum, substantially as so far described, is disclosed in Patent3,099,543, issued to Malmstrom et al. on July 30, 1963, and assigned tothe same assignee as the present application.

Steam under pressure is supplied to the interior of the drier drum bymeans of steam supply pipes 38 having rows of steam discharge openings39 formed therein and extending axially of the drier drum along theshaft 13. The pipes 38 are connected to the compartment 30.

The condensate removal system of the invention comprises a pair ofmanifolds 40 and 41 positioned oppositely from each other with respectto the shaft 13 and located adjacent the inner surface `of the shell 10.Each of the manifolds 40 and 41 is rectangular in cross section, asshown in FG. 5, and comprises a pair of elongated hollow shells 42 and43, which are welded together at their edges. Each manifold 40 and 41 issupported from adjacent staying members 20 by means of A-shaped brackets44. Each of the brackets 44 has one -of its legs bolted to a stayingmember 20 and carries a U-shaped bar 45 on its uppermost portion whichis indented to receive a manifold 40 or 41, and the manifold is weldedto the bar 45. Each manifold is supported from the sections 18 by meansof brackets 46 which are welded to the manifold adjacent its ends andwhich are bolted to the sections 18.

A plurality of small diameter tubes 47 extend radially through theoutermost wall 43a of ea-ch of the manifolds 40 and 41. The tubes havetheir outer ends 48 terminating adjacent the inner surface of the shell10 and have their inner ends 49 terminating well within the associatedmanifold, preferably at least to the center of the manifold. In theparticular embodiment lof the invention illustrated, each of themanifolds 40 and 41 is provided with thirty-two of the small diametertubes 47 which are located on 2% inch centers.

Each of the manifolds 40 and 41 has four equally spaced, relativelylarge diameter condensate withdrawal tubes 50 extending into it throughits innermost wall 42a. The outer end 51 of each of the tubes 50 islocated adjacent to the outer Wall 43a of the associated manifolds.

The tubes 50 of each of the headers are connected by means of branchpipes 52 and 53 with a central header 54 which is connected with thecompartment 29 in the shaft 13. The headers 54 are locatedequi-distantly from the heads 11 and 12 except that the headers areangled to the left as seen in FIG. 1, toward the separator 28, to avoidthe flanges 25 and 26 in passing through the shaft 13 into thecompartment 29.

The tubes 47 are preferably of different lengths, the tubes 47 locatedcloser to the withdrawal tubes 5t) being longer than the tubes remotefrom the Withdrawal tubes 50, in order that there shall be morerestriction to the flow `of lcondensate and steam through the smalltubes 47 located closer to the Withdrawal tubes 50 than through theother tubes 47. Insofar as length is concerned, the tubes 47 in theillustrated embodiment may be designated as the different length tubes47a, 47b, 47C, and 47d. The tubes 47d are longer than the tubes 47C,which in turn are longer than the tubes 47b, and the tubes 4717 arelonger than the tubes 47a. Between each group of tubes there may, forexample, be a difference of length of 1/2 inch. The tubes 47a in theparticular illustrated embodiment terminate substantially midway betweenthe manifold Walls 42a and 43a, and the tubes 47b, 47C, and 47dterminate respectively at additional distances of 1/2 inch from thelouter wall 43a of the manifold. The withdrawal tubes 50 extend radiallyoutwardly substantially closer to the outermost wall 43 than the innerends of the shortest tubes 47a, the tubes 50 having their ends 51located an inch, for example, from the ywall 43a of the manifold whilethe short tubes 47a terminate 3 inches, for example, from the outer wall43a.

Although, as will be obvious, the internal diameter and length of thetubes 47 lmay be varied; in one particular embodiment -of the invention,the bores of the tubes 47 were .307 inch in diameter and the tubesvaried in length from 5% inches t-o 6% inches. The tube ends 48 may belocated, for example, from 1/s inch to inch from the internal surface ofthe shell 10, and a good working distance in actual practice between thetube ends 48 and the internal shell surface has been found to be about/l@ inch, The large diameter condensate withdrawal tribes 50 had-aninternal diameter `of one inch in this embodiment.

In operation, moist paper web is directed onto the outer surface -of theshell 10, `and the drum may be rotated by means of the sprocket or otherdriving mechanism on the extension 35 at a high speed, such as 4,000 to5,000 feet per minute, for example. The web is dried as the drumrotates, and the web maybe creped ofic the outer surface of the drum bymeans of a suitable creping blade (not shown).

Steam under pressure is supplied to the compartment 30 through the bore37, Vand the steam is directed into the internal compartment of the drumthrough the supply pipes 38 and the discharge openings 39 in the pipes38. The steam heats the drier drum, and, in doing so, it condenses intoWater; `and the water condensate rims the internal surface of the shell10 completely around the shell, to a depth of 1A inch, for example. The`condensate removal system, including the manifolds 40 and 41 and thesmall diameter tubes 47, remove this condensate.

To maintain the surface temperature and the drying effect of fthe shell10 as uniform as possible, the depth of the water condensate ismaintained as uniform as possible about the internal surface of theshell 10. Steam within the drier drum rushes to the ends 48 of the tubes47 located close to the internal drum surface, since the pressure withinthe tubes 47 and in the connected manifolds 40 and 41 and compartment 29is lower than the pressure of the steam within the drum. The steam, inentering the ends 48 of :the small diameter tubes 47 sweeps across theinner turface of the drier drum, and atomizes the condensate existing onthe inner drum surface. Thus, a steam-water mixture passes radiallyinwardly through the bores of the tubes 47 into the manifolds 40 and 41.In order that such atomization occurs, the velocity of the steamentering the bores of the small diameter tubes 47 is high, and thevelocity of the steamwater mixture within the tubes 47'may be, forexample, about 110 feet per second. The small diameters of the boresWithin the tubes 47 provide this high velocity; and, due to the highVelocity, the pressure within the bores of the tubes 47 is reducedfrom'the pressure within the drum by about 5 pounds' per square inch. i

' The steam-water' mixture flowing radially inwardly through the tubes47, of course, is subject to centrifugal force due to the high velocityof rotation of the drier drum; however, since there is atomization inthe vicinity of the ends 48 of :the tubes 47, the pressure of the steamwithin the drier drum is effective to move the water-steam mixtureinwardly against the centrifugal force. It will -be understood that ifsuch atomization should not occur, it would be more difficult to movetheundiluted condensate inwardly against centrifugal force due to itsincreased densityl .n

There is some condensation taking 'place within the manifolds 40 and 41,and the water-steam mixture in passing through the tubes 47 also tendsto separate into water and steam components; however, since the tubeends 51 are located quite close to the outer walls 43a ofthe manifolds40 and 41, substantially the same atomizing action takes place on thesewalls as takes place at the ends48 of the tubes 47. Due to centrifugalforce, water'in the manifolds 40 and 41 tends to pond on the outersurfaceA 43a, and the steam in sweeping across the ends 51 of the tubes50 tends to atomize any water on the outer walls 43a of the manifolds 40and 41 and draws it along with the steam as a water-steam mixtureradially through the tubes 50 and into the compartment 29 of the shaft13 by means of the pipes 52, 53 and 54. The velocity of the steam-watermixture through the tubes 50 may be, for example, 80 to 90 feet p ersecond.

The compartment 29 is connected through the bore 36 within a suitablesteam condensate separator (not shown), and the pressure of steam withinthe compartment 29 i-s controlled by any suitable valve means (notshown). It will be understood, of course, that the steam pressure drops,in general, from the tube ends 48 through the manifolds 40 and 41 andthrough the pipes 53 and 54 and through the compartment 29, as thesteam-water mixture flows to the separator. The steam pressure, forexample, may drop from about 125 pounds per square inch within the drierdrum to 110 pounds per square inch within the bore 36.

Due to the atomization of the condensate on the outer walls 43a of themanifolds 40 and 41, the walls 43a are swept relatively clean of waterso that there is no flooding of the manifolds, and hence no impedance byflooding to any flow of a Water-steam mixture through the small diametertubes 47. The tubes 47 cannot be blocked particularly due to the factthat the inner ends 49 of the tubes are located closed to the center ofrotation of the shell than are the ends 51 of the tubes 50, and hencethe inner ends 49 of the tubes 47 protrude clear of any water ponded onthe surfaces 43a.

It will be observed that the steam-condensate mixture travels from theends 48 of the tubes 47 to the compartment 29 in two -stages in each ofwhich there is a sweeping action of the steam across la surfaceatomizing the water condensate; and the structure providing thistwostage action has been found to provide more uniformity of condensateremoval lengthwise of the drier drum and lengthwise of the manifolds 40and 41 than if there were a simple direct connection between each of thesmall diameter tubes 47 and the compartment 29. If there are any waterponds on the surfaces 43a caused by centrifugal forces, the largediameter tubes 50 tend to be immersed in these water ponds; and theatomizing action at the ends 51`of the tubes 50 functions to providesubstantially the same reduced pressure within the manifolds 40 and 41from one end to the other end of each manifold. Therefore, all of thesmall diameter tubes 47 have nearly the same pressure effective at theirinner ends 49 so that condensate ow in all of the tubes 47 is fairlyuniform. Y

In order to take care of the slight variations in pressure that existwithin the manifolds 40 and 41 adjacent and remote from the outlet tubes50, the tubes 47d located close to the tubes 50 have been made longerthan the tubes 47a remotely located with respect to the tubes 5ft,V andthe intermediate :tubes 47b and 47C are intermediate in length withrespect to the tubes 47a and 47d. The impedance to flow of thewater-steam mixture through the tubes 47, of course, increases with :thelength of the tubes 47; and, `since there is a slightly greater tendencyto draw water-steam mixture out of the tubes 47 located closer toy theoutlet tubes 50, the tubes 47 remotely located with respect to theoutlet tubes 50 have been made shorter so as to equalize the flow ofwater condensate mixture through the various tubes 47. Also, inequalizing the flow, the headers 54'have been located centrally withinthe drier drum, except for the slanting portionsof the headers 54leading to one side of the anges 25 and 26.

The above-described condensate removal system advantageously isnon-flooding with respect to the small diameter tubes 47 due to the factthat the large diameter tubes 50 extend in close proximity to thesurface 43a of the manifolds and the tubes 47 extend inwardly 'beyondthe ends 51 of the tubes 50. The two-stage action of the condensatewithdrawal system also assures quite substantial uniformity ofcondensate withdrawal from one end to the other end of each of themanifolds 40 and 41,

this two-stage action constituting the atomizing effect of the smalldiameter tubes 47 on the internal surface of the shell 10 and theatomizing effect of the ends 51 of the large diameter tubes 50 withrespect to the adjacent internal surfaces 43a of the manifolds 40 and41. In order to correct any minor discrepancies of flow through thetubes 47,'the tubes47 are also preferably made greater in lengthadjacent the outlet 1tubes 50, as described.

We wish it to be understood that the invention is not to be limited tothe specific constructions, arrangements and devices shown anddescribed, except only insofar as the claims may be so limited, as itwill be understood to those skilled in the art that changes may be madewithout departing from the principles of the invention. In particular,we would like to have it understood that, although the tubes 47 areshown exactly radially, these tubes could, if desired, be set at anangle with respect to radii of the drier drum and also with respect tothe tubes 50. Also, it will be understood that, although we havedisclosed only two manifolds 40 and 41, additional similar manifolds maybe added to the construction` What is claimed is:

1. A hollow dr-ier drum having journals for rotatably mounting the drum,a steam supply connection for didecting steam into the drum, `a manifoldin said drum and lying adjacent to the inner surface of the drum, aplurality of water condensate removal tubes extending into and carriedby said manifold and terminating closely adjacent to the inner drumsurface, and a water condensate removal pipe connected to a condensateremoval connection and extending outwardly into said manifold, said pipeextending farther outwardly radially than the inner ends of said tubesso as to prevent blockage by condensate of said tubes.

2. A hollow drier drum having journals for rotatably mounting the drum,a steam supply connection for direct-ing steam into the drum, aplurality of manifolds in said drum lying adjacent to the inner surfaceof the drum and equi-distantly spaced from each other, a plurality ofwater condensate removal tubes extending generally radially into andcarried by each of said manifolds and terminating on their outer endsclosely adjacent to the inner drum surface, and a plurality ofcondensate removal pipes connected to a condensate removal connectionand extending generally radially into each of said manifolds, said pipeshaving their outer ends terminating closer to the outermost wall of saidmanifolds than the inner ends of said tubes so as to prevent blockage ofcondensate of said tubes.

3. A drier drum having journals for rotatably mounting the drum, a steamsupply connection for directing steam into the drum, .a plurality ofmanifolds in said drum and extending generally axially of the drumadjacent to the inner drum surface and equi-distantly spaced from eachother, a plurality of water condensate removal tubes extending generallyradially into and carried by each of said manifolds and terminating ontheir outer ends closely adjacent to the inner drum surface, and aplurality of water condensate removal pipes connected to a condensateremoval connection .and extending generally radially into each of saidmanifolds and equi-distantly spaced along the length of the manifold,the inner ends of said tubes extending further inwardly radially of thedrum than the outer ends of said pipes and certain ones of the tubes.adjacent to said pipes in each of said manifolds being longer thanother ones of said tubes which are more remote from said pipes forequalizing the flow of condensate through said tubes and into saidmanifolds.

4. A hollow drier drum having journals for rotatably mounting the drum,a steam supply outlet in said drum 4and connected to one of saidjournals for directing steam into the drum, a plurality of manifolds insaid drum and extending generally axially of the drum adjacent to theinner drum surface and equi-distantly spaced about the drum, a pluralityof water condensate removal tubes of relatively small diameter extendingradially into and carried by each of said manifolds and terminatingclosely adjacent to the -inner drum surface, .a plurality of watercondensate removal pipes extending radially into each of said manifoldsand having a water removal connection with the other of said journals,said pipes being substantially less in number than the number of saidtubes and being of larger internal diameter than said tubes and beingequally spaced along each of said manifolds, said pipes terminatingclosely adjacent to the outermost surfaces of said manifolds and saidtubes terminating within the manifolds farther from said outermostmanifold surfaces than said pipes.

5. A hollow drier drum having journals for rotatably mounting the drum,a steam supply connection for directing steam into the drum, a manifoldin said drum and lying adjacent to the inner surface of the drum, aplurality of water condensate removal tubes extending into and carriedby said manifold and terminating closely adjacent to the inner drumsurface, a condensate removal connection, and water condensate removalpiping connected to said condensate removal connection and to saidmanifold and terminating farther outwardly in the manifold than theinne-r ends of said tubes so as to prevent blockage by condensate ofsaid tubes.

6. A hollow drier drum having .a hollow central axle with end journalsfor rotatably mounting the drum, a steam supply connection for directingsteam into the drum, a plurality of manifolds in said drum and equallyspaced about the drum and lying adjacent to the inner surface of thedrum, a plurality of water condensate removal tubes extending into andcarried by each of said manifolds and terminating closely adjacent tothe inner drum surface, said .axle being vented through one of saidjournals so as to provide a Water condensate removal connection, andwater condensate removal piping connected to said axle and alsoconnected to each of said manifolds at a place in each of said manifoldslocated farther outwardly than the inner ends of said tubes so as toprevent blockage of condensate of said tubes.

References Cited by the Examiner UNITED STATES PATENTS 3,169,050 2/1965Kroon 34-l24 DONLEY I. STOCKING, Primary Examiner. A. D. HERRMANN,Assistant Examiner.

1. A HOLLOW DRIER DRUM HAVING JOURNALS FOR ROTATABLY MOUNTING THE DRUM,A STEAM SUPPLY CONNECTION FOR DIDECTING STEAM INTO THE DRUM, A MANIFOLDIN SAID DRUM AND LYING ADJACENT TO THE INNER SURFACE OF THE DRUM, APLURALITY OF WATER CONDENSATE REMOVAL TUBES EXTENDING INTO AND CARRIEDBY SAID MANIFOLD AND TERMINATING CLOSELY ADJACENT TO THE INNER DRUMSURFACE, AND A WATER CONDENSATE REMOVAL PIPE CONNECTED TO A CONDENSATEREMOVAL CONNECTION AND EXTENDING OUTWARDLY INTO SAID MANIFOLD, SAID PIPEEXTENDING FARTHER OUTWARDLY RADIALLY THAN THE